To obtain an excellent high-temperature oxide superconducting wire, it is necessary to form an intermediate layer having high crystal orientation (CeO2 or zirconia doped yttrium oxide (YSZ)) and a superconducting film (RE123 film: RE: Y, Gd, Ho or the like) on a metal substrate.
As a method of forming these oxide films, conventionally, there have been known an ion-beam-assisted deposition method (IBAD method) and a RABITS method where an oxide film is formed on a metal substrate which is biaxially textured in advance.
To take future production efficiency such as a film forming speed into consideration, an oxide superconducting wire manufactured on the RABITS (biaxially textured substrate)method is advantageous. However, to enhance the superconducting property, it is important to make crystals of the metal substrate highly oriented.
As such a metal substrate, there has been disclosed a substrate where copper is laminated to a stainless steel substrate, and is biaxially textured, and an intermediate layer made of nickel is laminated to the copper layer (see patent document 1, for example).
Further, as a method of manufacturing such a metal substrate, there has been disclosed a technique where copper is subjected to high rolling reduction and is biaxially textured by heat treatment, the biaxially textured copper is laminated to a stainless steel substrate by cold rolling, and a nickel layer is laminated to the copper layer (see patent document 2, for example).